(1) Field of the Invention
The present invention relates to a computer and more particularly to a computer capable of being used while retaining high reliability even in such an environment as outdoor environment or the like.
(2) Description of the Related Art
Heretofore, personal computers have widely been used for performing various calculations, and a portable, small-sized computer has recently been developed.
In such a small-sized computer, however, since extremely precise electronic components are incorporated therein, its impact resistance is very low, and when impact is exerted on the computer, for example, by dropping from a desk or the like or collision with something, the computer will be damaged, causing malfunction or inoperative state.
Generally, in computers used for various information processings, electronic devices incorporated therein are easily effected by humidity, so such computers are used in a less humid environment.
In recent years, however, there has been an increasing necessity of performing information processings using computers in bad, outdoor working environments such as, for example, construction work site and engineering work site. In such outdoor environments, however, it is very likely that there will occur dropping, etc. of the computers, so it has been necessary to protect the computers positively.
In the case of using a computer in an outdoor place exposed to rain water, a special booth for shielding the computer from rain water has heretofore been installed at the work site and the computer has been used within such special booth. However, the installation of such special booth is very expensive and requires a large installing space, so its installation has so far involved a great deal of trouble.
According to the prior art, in view of such inconvenience, the whole of a computer is put into a protective case which is provided as an optional item for example to protect the computer from external shock, etc.
According to the prior art, moreover, when waterproofness is to be ensured, a computer is used in a wholly covered state using a waterproof cover such as a transparent resin sheet or the like.
However, the above method of accommodating a computer within a protective case involves the problem that it is impossible to operate the computer as housed within the protective case.
It is possible to form an opening in part of the protective case so that the computer as housed within the case can be operated. Even in this case, however, it is extremely difficult to ensure a safe operability. Moreover, even if impact resistance is improved by the protective case, the entire size will become extremely large and thus the use, especially outdoor use, is very inconvenient. Further, in a received state within the protective case, the interior of the case will be filled with heat generated from the computer, thus giving rise to the problem that electronic components, etc. of the computer are badly influenced.
According to the conventional means adopted for solving the aforementioned problems, an impact-resistant member is mounted replaceably, or fixed using an adhesive or the like, at each corner portion of the computer body case. However, in the use of such conventional computer protecting means using a replaceable impact-resistant member, it is necessary to provide such impact-resistant member separately, thus resulting in increase in the number of components and increase of the material cost. Besides, the space for mounting such impact-resistant member is required inside the computer body case, thus obstructing the attainment of the reduction in size of the body case. Further, since the impact-resistant member is mounted in a replaceable manner, the mounting strength of the impact-resistant member with respect to the body case may be insufficient, causing disengagement of the impact-resistant member from the body case, and thus it is impossible to ensure protection of the computer. Additionally, the use of some impact-resistant member mounting means may result in difficulty in retaining the waterproofing function of the computer body case.
In the case of the foregoing computer protecting means which uses an adhesive or the like for fixing the impact-resistant member to the computer body case, the durability of the impact-resistant member will be deteriorated markedly if the bonding strength of the adhesive used is insufficient. Besides, some impact exerting direction may give rise to a difference in impact resistance, thus making it impossible to ensure the protection of the computer. Further, since an adhesive applying step is required, the number of manufacturing steps increases, thus resulting in increase of the manufacturing cost.
In the case of using a waterproof cover, the rupture of the same cover is very likely to occur and thus the waterproofness of the computer cannot be ensured to a satisfactory extent. Besides, the information inputting operation, etc. through such waterproof cover are inconvenient and thus the working efficiency is very poor.
Under such circumstances, it has been desired to develop a computer which is employable even in bad working environments.
For making a computer portable, it is necessary to use a battery which is small in size but can work long. As a battery which satisfies this condition there is known a nickel-hydrogen battery for example. This type of a battery is formed so as to permit leakage of an explosive gas such as hydrogen gas to the exterior through an explosion-proof valve upon occurrence of a trouble. Therefore, in the case of using a battery which generates such explosive gas, it may be suitable to mount the battery outside the computer case. In this case, however, the battery is apt to be disengaged from the computer case due to low vibration resistance thereof upon imposition thereon of a large shock such as dropping of the computer. Moreover, the electrodes of the battery are apt to become rusty, and also from the standpoint of waterproofness, its attainment is difficult. Further, since the battery is exposed, the appearance is not good.